The present invention relates to EDM apparatus provided with several electrode tools capable of being used in sequence.
It is known to provide EDM apparatus with an automatic tool changing mechanism, whereby the diverse electrode tools are stored in a magazine and a tool conveyor is provided between the magazine and the tool holder for carrying the electrode tools between the magazine and the tool holder and for returning the electrode tools to the magazine. For example, with the tools stored in a magazine such as a rotatable table, the tool conveyor system comprises, in general, a moving arm arranged such as to take a tool from the rotatable table and carry it to the tool holder of the machining head. After the tool has been installed on the tool holder, the moving arm must be retracted such as to clear the machining head to enable the electrode tool to be displaced to a position proximite the workpiece.
Tool conveyor systems and moving arms take much room and are a hindrance to designing a compact tool changer. In addition, known tool changers and conveyors must achieve motion of the tool along the three axes, which is a requirement that results in complex and costly devices.